Synthesis And Selective Recognition Toward Zinc Ion Of Chiral Poly(Imine-Triazole)

A novel AB type of clickable monomer, (S)-2-[(2-azido- 1-phenylethylimino)methyl]-5-propargyloxyphenol (AMPP) was designed and polymerized to yield a class of main-chain chiral poly(imine-triazole)(s) through the metal-free click reaction. With the thermally induced polymerization, the desired polytriazoles can be easily prepared in high yields by a stepwise heating-up process and have the number-average molecular masses ranging from 5.1 x 10(3) to 58.1 x 10(3) (polydispersity indices = 1.38-1.68). The polymers were characterized by Fourier Transform Infrared spectroscopy (FTIR), H-1 Nuclear Magnetic Resonance (NMR), and gel permeation chromatography, and their optical properties were studied by fluorescence and circular dichroism (CD) spectroscopies. As a chemosensor, these polymers exhibited a selective "turn-on" fluorescence enhance-ment response toward Zn2+ ion over other cations such as Na+, K+, Mg2+, Ca2+, Ag+, Pb2+, Cd2+, Hg2+, Mn2+, and Ni2+ in dimethyl sulfoxide. However, the Zn2+ -induced fluorescence signal was subject to serious interference by Al3+, Cu2+, Cr3+, and Fe3+ ions. Interestingly, the chiral polymer showed distinctive changes in the CD spectra on complexation with Zn2+, which allowed for the discrimination of this ion in the presence of other species tested including those interfering ions observed in the fluorescent detection. (c) 2014 Wiley Periodicals, Inc.